Radon Threat May Extend Beyond Reading Prong

March 10, 1986|by ROBERT HANLEY, The New York Times

Potentially harmful levels of radon, a radioactive gas that can cause cancer, may be contaminating homes over a much wider area of New York, New Jersey and Pennsylvania than previously believed, according to scientific experts and public health officials.

Only months ago, scientists' concern about radon seeping into homes centered on the Reading Prong, a geological formation containing uranium deposits that runs from Reading, Pa., across parts of seven counties in northwestern New Jersey into sections of Orange, Rockland, Putnam and Dutchess Counties in New York.

New tests and surveys, indicate that the hazard from radon, which occurs naturally as a byproduct of decaying uranium, may extend well beyond the Reading Prong.

While radon has long been known to be the most prevalent form of naturally occurring radiation in the environment, it was considered of little risk because it is easily dispersed in the atmosphere. Testing in homes began only in mid-1985, after an engineer with a Pennsylvania utility set off radiation alarms when he entered a nuclear plant. Tests at his home above the Reading Prong found radon levels far above that allowed in uranium mines.

The risk of long-term exposure to residents is not well documented and remains the subject of debate, but the National Cancer Institute considers radon the second leading cause of lung cancer in the United States, after cigarette smoking.

Within a month, the EPA plans to issue a set of risk guidelines for indoor exposure, though they are not expected to differ greatly from the EPA limits now in use. The guidelines are intended to help states set their own safety guidelines, change building codes to lessen risks and take other measures.

Last week the New York State Health Department sponsored a conference in Albany to help New York devise a radon strategy. At the conference, officials made these assessments:

- In Pennsylvania, according to Thomas Gerusky, the director of that state's Bureau of Radiation Protection, "All of eastern Pennsylvania has the potential for excessive radon - there's enough uranium there."

- In New Jersey, where concern has centered on 250,000 homes and other buildings on top of the Reading Prong, recent surveys suggest uranium lies under much of the northern half of the state, an area with 1.6 million buildings. "We can't eliminate them as a problem," said Dr. Gerald P. Nicholls, acting chief of the state's Bureau of Radiation Protection.

- In New York, which has not conducted surveys as extensive as those in Pennsylvania and New Jersey, recent soil tests found radon on the Reading Prong in Highland Falls, near West Point in Orange County, and in veins of shale near Syracuse and Buffalo. The shale is common throughout the Mohawk Valley and the Southern Tier.

"It is a very significant public health threat," said Dr. David Axelrod, the New York State Health Commissioner. "The time has now come for those in the Northeast to deal with the realities of the problem."

Radon is a colorless, odorless gas emitted by rocks and soil just about everywhere, usually in small concentrations. Scientists say that in concentrated form it is the most dangerous and most prevalent form of naturally occurring radiation in the environment.

Radon is created by the decay of radium, a byproduct of uranium decay. As the radon itself decays, scientists say, it produces alpha-emitting particles of polonium - another radioactive element. Polonium, if inhaled, can lodge in the sensitive tissue of the lung's airways and over years damage cells and create cancers, the scientists say.

Federal health and environmental officials believe radon causes from 5,000 to 20,000 of the 100,000lung cancer deaths each year in the United States.

Experts base their risk estimates on incomplete studies of lung cancer among uranium miners in Colorado, Wyoming and Utah. Many of the miners involved in the studies are still alive, and only after the final number of fatal lung-cancer cases is known will the researchers be able to determine the risk to the general public more precisely.

The public's exposure to radon is expressed in terms of "working levels," essentially because the only safety standards defined so far deal with protecting uranium miners from overexposure.

For years, scientists have known that outdoor exposure to radon was unavoidable. What has startled radon experts in the last few months are the radon concentrations being found inside homes.

Since mid-1985, 44 houses have been found in Pennsylvania at 1 working level. All are on the Reading Prong, including 10 near Easton, according to Gerusky.

For every 1,000 people exposed to 1 working level in the home for 75 percent of their lifetimes, more than 500 will die of lung cancer, according to risk assessments now used by the federal EPA.